粒间胶结接触力学特性的三维试验研究

为实现结构性砂土离散元接触模型合理性的三维试验验证，设计了一套可用于三维半球形理想胶结颗粒成型及实现不同加载条件下的接触力学特性测试装置，制备了一定胶结尺寸的环氧树脂半球形颗粒胶结试样，在一系列辅助加载装置中初步开展了不同加载条件（拉伸、压缩、剪切、弯转、扭转）下的力学性能测试。结果表明，该装置可用于实现三维情况下胶结颗粒接触力学特性测试；不同加载条件下的实测试验结果与二维试验成果基本一致；峰值剪切、弯矩、扭矩随着法向荷载的增大呈现先增大后减小的趋势，存在一个相同的临界法向荷载。

Three-dimensional experimental study of mechanical behaviors of bonded granules

In order to verify contact model and parameter rationality for structured sand in discrete element simulation, a set of apparatus for specimen preparation and tests on contact mechanical behaviors of idealized hemispherical bonded granules are designed. Throughout the specimen preparation devices, two aluminum hemispheres with the same size were cemented together by adhesive in a size-controlled mode. Then, a series of tests were conducted, including tension test, compression test, shear test, bending test and torsion test, using secondary loading devices. The results show that the apparatus are able to investigate the contact mechanical behaviors of two bonded hemispheres. The consequences are in good agreement with those extracted from the achievements of 2D tests in references. The peak shear force, bending moment, torque of two bonded hemispheres increase to a peak value with the normal force firstly, and then decrease with the normal force. In addition, the critical normal forces in different loading conditions are almost the same.